The purpose of the proposed Imaging Core is to provide Program investigators access to state-of-the-art multicolor confocal and two- photon excitation microscopy, and associated digital imaging processing and 3-D reconstruction software in the laboratory of Dr. David Piston. The capabilities of this instrumentation and software greatly exceed those currently available to all Vanderbilt faculty on a fee-for-service basis in the Vanderbilt Cell Imaging Resource Core. These enhanced imaging capabilities are required for individual projects that comprise the program. Dr. Piston is an internationally recognized expert in digital might microscopy and quantitative imaging. By engaging him as a full scientific participant in the Program, collaborations and interactions between Dr. Piston and the project leaders will undoubtedly result in the development of new methods and approaches for studying C. elegans.